This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

See massive fossils that are over 200 million years old in northeastern Arizona.

Left untouched since a double murder-suicide in the 1960s, Los Feliz murder mansion remains a neighborhood mystery.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

One of only two commuter aerial tramways in the United States.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The world's longest known cave system.

Ride the subways of yesteryear.

A dilapidated dock tells the story of Titanic's missed arrival.

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

Resting place of Hollywood's immortals is also site of summer film screenings.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

A snapshot of the city's fascinating voodoo culture.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A chilling disappearance (and rescue) of a child uncovers a geological mystery.

You thought Santa Claus didn't exist, but it turns out you were wrong.

This elaborate estate contains a stunning marble aviary, a sunken conservatory, and a magnificent music room with a two-story pipe organ.

This mysterious hill seems to pull objects uphill.

The sign to a demolished amusement park now stands in front of a local library.

Known as the "Cross At The Crossroads," this massive metal cross is just short enough to avoid the FAA.

A towering Art Deco movie palace made to look like a Mayan temple.